- Density... If it is 3.8g/ml is it not chromium. The only metal or metallic mineral that fits with approximately that density and a hardness around 7 is hibonite, which is black - so something's not right. Please could you check your denisty measurements/calculations...

If you can tell me the streak colour (as per link above) and check the density, we have a good chance of making a reasonable determination ourselves. If we find that nothing fits the data, you could send it somewhere for analysis. No point sending it to me, I'm afraid. Although I'm uni trained as a geologist, I don't have access to a lab these days. You'd need to find a lab with suitable equipment such as a mass spectrometer or an electron microprobe. Maybe you have a university with an earth science / geology dept. nearby? If so, there's a good chance they'd be able to find somebody to make a comment, and possibly guide you onwards in your quest, eg. to somewhere with suitable equipment. There's a good chance, however, that you'd be charged for the analysis. You could also try a local geology club as a starting point.